I suppose this is almost as much a medical question as it is a technical one, but here goes. I have epilepsy, which, although fairly well controlled, does have its problems and I have to be careful with certain activities. The question no one seems to be able to answer is, can EVF viewfinders bring on or give AME-specific problems? This has to be considered now by me, as there are some great cameras available and an increasing number use an EVF. It’s a big investment, though, and I wonder if I am going to have a problem using them. I can use a computer, but limit my time and cannot play games, for example, so would these EVFs be a ‘no-no’ for me? - Mark Stufanberg

Ultimately, the only answer that we can give to this is to seek medical advice. Without knowing whether you suffer from photosensitive epilepsy or what has triggered seizures in the past, it’s impossible for anyone to say whether or not you might experience any problems using an EVF. Even armed with that information we would still need to speak to a medical expert, and we would suggest that you are in a much better position to describe your condition than we are. What we can do, though, is confirm that there is a possibility that an EVF could trigger a seizure if you have photosensitive epilepsy.

Essentially, an EVF is a small LCD screen. According to Epilepsy Action (www.epilepsy. org.uk), LCD screens (in the context of TVs and monitors) ‘are far less likely to trigger a seizure than CRT screens. However, the risk of having a seizure is not removed entirely.’ The key phrase there is ‘not removed entirely’: an LCD screen (and by extension an EVF) could act as a trigger for some people.

The problem is, an LCD screen needs to be ‘refreshed’, and this cycling of the onscreen image is what can lead to a seizure. Epilepsy Action states that ‘most people with photosensitive epilepsy are sensitive to 16-25Hz’, while The Epilepsy Society (www. epilepsysociety.org.uk) suggests ‘between 3-30 hertz (flashes per second) are the common rates to trigger seizures’. While the ‘common’ range may vary, what both organisations agree on is that some people may be sensitive to frequencies up to 60Hz.

The problem here is that not all EVFs are equal, and not all manufacturers are open about their refresh rates – some will undoubtedly fall below 60Hz. Again, the key is that even 60Hz can affect ‘some people’, and you could be one of them. So, as we said at the start, speaking to your GP or a specialist is the only answer we can give.